Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 270
Filter
1.
J Cyst Fibros ; 23(2): 262-268, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38104000

ABSTRACT

BACKGROUND: Gut dysbiosis is implicated in colorectal cancer (CRC) pathogenesis. Cystic fibrosis (CF) is associated with both gut dysbiosis and increased CRC risk. We therefore compared the faecal microbiota from individuals with CF to CRC and screening samples. We also assessed changes in CRC-associated taxa before and after triple CF transmembrane conductance regulator (CFTR) modulator therapy. METHODS: Bacterial DNA amplification comprising V4 16S rRNA analysis was conducted on 84 baseline and 53 matched follow-up stool samples from adults with CF. These data were compared to an existing cohort of 430 CRC and 491 control gFOBT samples from the NHS Bowel Cancer Screening Programme. Data were also compared to 26 previously identified CRC-associated taxa from a published meta-analysis. RESULTS: Faecal CF samples had a lower alpha diversity and clustered distinctly from both CRC and control samples, with no clear clinical variables explaining the variation. Compared to controls, CF samples had an increased relative abundance in 6 of the 20 enriched CRC-associated taxa and depletion of 2 of the 6 taxa which have been reported as reduced in CRC. Commencing triple modulator therapy had subtle influence on the relative abundance of CRC-associated microbiota (n = 23 paired CF samples). CONCLUSIONS: CF stool samples were clearly dysbiotic, clustering distinctly from both CRC and control samples. Several bacterial shifts in CF samples resembled those observed in CRC. Studies assessing the impact of dietary or other interventions and the longer-term use of CFTR modulators on reducing this potentially pro-oncogenic milieu are needed.


Subject(s)
Colorectal Neoplasms , Cystic Fibrosis , Feces , Gastrointestinal Microbiome , Humans , Cystic Fibrosis/microbiology , Cystic Fibrosis/complications , Colorectal Neoplasms/microbiology , Colorectal Neoplasms/etiology , Male , Feces/microbiology , Adult , Female , Dysbiosis/microbiology , Middle Aged , RNA, Ribosomal, 16S/analysis
3.
Air Qual Atmos Health ; 15(12): 2239-2254, 2022.
Article in English | MEDLINE | ID: mdl-36187166

ABSTRACT

Wildfires have increased in the last years and, when caused by intentional illegal burnings, are frequently run out of control. Wildfire has been pointed out as an important source of polycyclic aromatic hydrocarbons (PAHs) and trace elements (TEs) - such as, As, Ni, and Pb - to environmental compartments, and thus may pose a risk to human health and to the ecosystem. In 2020, the Brazilian biome, Pantanal, faced the largest losses by wildfires in the last 22 years. Ashes from the topsoil layer in Pantanal were collected after these wildfires at 20 sites divided into the sediment, forest, PF, PS, and degraded sites. Toxicity and associated risks for human health were also evaluated. The areas highly impacted by wildfires and by artisanal gold mining activities showed higher concentrations for TEs and PAHs than the protected areas. Pb varied from 8 ± 4 to 224 ± 81 mg kg-1, and total PAH concentration ranged between 880 ± 314 and 1350 ± 70 ng g-1, at sites impacted by anthropogenic activities. Moreover, health risk assessments for TE and PAH indicated a potentially great risk for children and adults, via ingestion, inhalation, and dermal pathway. The carcinogenic risks exceeded reference values, for both TE and PAH, suggesting harmful conditions, especially for vulnerable groups, such as children and the elderly. Supplementary Information: The online version contains supplementary material available at 10.1007/s11869-022-01248-2.

4.
Sci Total Environ ; 754: 141730, 2021 Feb 01.
Article in English | MEDLINE | ID: mdl-32920380

ABSTRACT

The evaluation of mercury (Hg) toxicity in wildlife species has prompted a search for sensitive indicators to accurately measure the body burden of Hg. Despite the extensive use of feathers as an indicator of Hg in birds, they do not appear to be an entirely suitable indicator of the extent of contamination in certain conditions and bird species since Hg levels are influenced by the growth period, timing of the last moult and migration. This research aimed to evaluate rhamphotheca as a potential indicator of environmental Hg concentrations in seabirds. We used culled yellow-legged gulls (Larus michahellis) (n = 20) and determined THg in rhamphotheca and feathers. We distinguished between upper and lower rhamphotheca, and divided each one into 16 equal portions along the culmen to analyse their THg content spatially. In each bird, THg was also determined in primary (P1) and secondary (S8) feathers and compared with rhamphotheca. The median (25th, 75th percentile) rhamphotheca Hg concentration was 13.44 (9.63, 17.46) µg/g, which was twofold higher than in the feathers 7.56 (4.88, 12.89) µg/g. Median THg in rhamphotheca was significantly higher (p < 0.05) in females 15.05 (10.35, 23.04) µg/g than in males 12.34 (8.57, 15.19) µg/g, whereas no differences (p > 0.05) were found in the feathers. No significant differences in Hg levels were found between upper and lower beak mandibles or along either. In contrast, significant differences in Hg concentrations were found between the P1 and S8 feathers (mean, 12.04 vs. 6.04 µg/g). No correlation was found between Hg content in rhamphotheca and feathers. Mercury levels in rhamphotheca exhibited stronger significant relationships with weight (R2 = 0.568), length (R2 = 0.524) and culmen (R2 = 0.347) than the levels in the feathers, which showed no correlation. Overall, our results suggest that rhamphotheca is a suitable tissue indicator for Hg monitoring in gulls; however, further studies are needed to extend our research to other bird species.


Subject(s)
Environmental Pollutants , Mercury , Animals , Birds , Environmental Monitoring , Environmental Pollutants/analysis , Feathers/chemistry , Mercury/analysis
5.
S Afr Med J ; 110(9): 835-836, 2020 08 12.
Article in English | MEDLINE | ID: mdl-32880262

ABSTRACT

The stated objective of the COVID-19 lockdown was to allow time to prepare healthcare facilities. Preparation must include administrative and environmental measures, which when combined with personal protective equipment, minimise the risk of the spread of infection to patients and healthcare workers (HCWs) in facilities, allowing HCWs to safely provide essential services during the pandemic and limit the indirect effects of COVID-19 caused by healthcare disruption. We present our model for facility preparation based on colour-coded zones, social distancing, hand hygiene, rapid triage and separate management of symptomatic patients, and attention to infection transmission prevention between HCWs in communal staff areas. This model specifically addresses the challenges in preparing a facility for COVID-19 in a low-resource setting and in rural areas. In addition, we include links to resources to allow workers in low-resource settings to prepare their facilities adequately.


Subject(s)
Coronavirus Infections/epidemiology , Delivery of Health Care/organization & administration , Health Facilities , Health Personnel , Pneumonia, Viral/epidemiology , Ambulatory Care Facilities , Betacoronavirus , COVID-19 , Capacity Building , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Disinfection , Environment Design , Hand Disinfection , Hospitals , Humans , Infection Control , Mobile Health Units , Pandemics/prevention & control , Personal Protective Equipment/supply & distribution , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , SARS-CoV-2 , South Africa/epidemiology , Ventilators, Mechanical/supply & distribution
7.
S. Afr. med. j. (Online) ; 0:0(0): 1-2, 2020.
Article in English | AIM (Africa) | ID: biblio-1271066

ABSTRACT

The stated objective of the COVID-19 lockdown was to allow time to prepare healthcare facilities. Preparation must include administrative and environmental measures, which when combined with personal protective equipment, minimise the risk of the spread of infection to patients and healthcare workers (HCWs) in facilities, allowing HCWs to safely provide essential services during the pandemic and limit the indirect effects of COVID-19 caused by healthcare disruption. We present our model for facility preparation based on colour-coded zones, social distancing, hand hygiene, rapid triage and separate management of symptomatic patients, and attention to infection transmission prevention between HCWs in communal staff areas. This model specifically addresses the challenges in preparing a facility for COVID-19 in a low-resource setting and in rural areas. In addition, we include links to resources to allow workers in low-resource settings to prepare their facilities adequately


Subject(s)
COVID-19 , Cross Infection , Health Care Facilities, Manpower, and Services , Health Personnel , Pandemics , South Africa
8.
Sci Total Environ ; 668: 723-729, 2019 Jun 10.
Article in English | MEDLINE | ID: mdl-30861408

ABSTRACT

Biotic mercury (Hg) methylation appears to depend on factors such as microbial activity and the concentration and bioavailability of Hg2+ to the Hg-methylating organisms. Recently, the presence of cyanobacteria has been linked with high methylmercury (MeHg) concentrations. The aim of this work was to test MeHg production in microcosms, in relation to the amount of periphytic cyanobacteria, dissolved organic matter (DOM) and phosphorus concentrations, as well as periphytic primary production rates. Water and periphyton samples were collected for cultivation and isolation of cyanobacteria from the Guaporé River floodplain, Brazil. We cultivated the periphyton in microcosms with different concentrations of cyanobacteria, total phosphorus and DOM. The highest net MeHg production (6.8 to 24.6% of added Hg d-1) occurred in the microcosm with added cyanobacteria, followed by microcosms with added phosphorus (6.1 to 11.4%) and added DOM (6.4 to 9.1%). Positive correlations were found between MeHg production, addition of cyanobacteria, phosphorus and DOM and periphytic primary productivity. Our results bring the first direct experimental evidence of the relevance of cyanobacteria and primary production as regulators of MeHg production in periphyton. These findings have numerous implications for the management of natural and engineered wetlands.


Subject(s)
Cyanobacteria/metabolism , Environmental Monitoring , Methylmercury Compounds/metabolism , Periphyton/physiology , Water Pollutants, Chemical/metabolism
9.
Eur Radiol ; 28(11): 4717-4724, 2018 Nov.
Article in English | MEDLINE | ID: mdl-29808426

ABSTRACT

OBJECTIVES: To assess patterns of parenchymal tissue on mammography in women with dense breasts and to determine how this varies with age and affects recall to assessment and cancer diagnosis. METHOD: Breast density data was obtained in women attending routine mammographic screening from April 2013 to March 2015 using automated breast density assessment software. Women with the densest breasts were selected for visual interpretation of parenchymal pattern (PP). One hundred non-assessed women, aged 50, 55, 60, 65 and 69-71 years (total = 500), provided controls. Cases included women recalled for assessment (mastectomy or implants excluded) (total = 280). Mammograms reviewed by ten readers and PP classified as: (1) very smooth; (2) mainly smooth; (3) mixed; (4) mainly nodular; (5) very nodular. The ratio of women in each category at each age and screening outcomes were compared by Pearson's chi-squared test. RESULTS: Reader agreement for scoring PP was good (intraclass correlation = 0.6302). Proportions of women in each PP category were similar at all ages for controls (p = 0.147) and cases (p = 0.657). The ratio of PP categories did not vary significantly with age in those who underwent biopsy (p = 0.484). Thirty-four cancers were diagnosed. There was a significant correlation between a diagnosis of cancer and nodular PP compared to not nodular PP (p = 0.043). CONCLUSIONS: The ratio of smooth to nodular pattern in women with the densest breasts did not vary with age. The PP of the breast tissue did not affect likelihood of recall to assessment or biopsy. There was a significant relationship between a nodular parenchymal pattern and diagnosis of cancer. KEY POINTS: • This paper shows that there is good agreement between mammogram readers when classifying mammographic PP on a five-point scale from very smooth to very nodular. • In non-assessed women with the densest breasts, there is no significant change in the proportions of smooth to nodular patterns with increasing age. • The likelihood of recall for further assessment or biopsy at assessment is not related to PP in women with highest breast density. • When recalled for further assessment, significantly more women are diagnosed with cancer in the group with nodular PP on mammography when compared with smooth and mixed patterns.


Subject(s)
Breast Neoplasms/diagnosis , Early Detection of Cancer/methods , Magnetic Resonance Imaging/methods , Mammography/methods , Mass Screening , Receptor, ErbB-2/metabolism , Receptors, Estrogen/metabolism , Adult , Biomarkers, Tumor/metabolism , Biopsy , Breast Density , Breast Neoplasms/epidemiology , Breast Neoplasms/metabolism , Disease-Free Survival , Female , Humans , Middle Aged , Netherlands/epidemiology , Survival Rate/trends
10.
Clin Radiol ; 73(8): 682-692, 2018 08.
Article in English | MEDLINE | ID: mdl-29773220

ABSTRACT

Needle core biopsy is considered the histological diagnostic method of choice for screen-detected breast lesions. Although the majority are definitively diagnosed as normal, benign, or malignant, approximately 7% are categorised as B3, of uncertain malignant potential. These include a wide range of lesions with different risks of associated malignancy from <2% to approaching 40% from literature review in UK practice. Historically, these have typically been surgically excised as a diagnostic procedure but the majority are then proven to be benign. An alternative approach, for many of these lesions, is thorough sampling/excision by vacuum-assisted biopsy techniques to exclude the presence of co-existing carcinoma. This would potentially reduce the benign open biopsy rate whilst maintaining accuracy of cancer diagnosis. A group from the Radiology, Surgery, and Pathology NHS Breast Screening Programme Co-ordinating Committees and an additional co-opted expert were charged with review and development of guidelines for the clinical management of B3 lesions. The guidelines reflect suggested practice as stated by the NHS Breast Screening Programme and approved by the Royal College of Radiologists.


Subject(s)
Biopsy, Large-Core Needle , Breast Neoplasms/pathology , Mass Screening , Breast Neoplasms/diagnostic imaging , Diagnosis, Differential , Early Detection of Cancer , Female , Humans , Neoplasm Grading , Predictive Value of Tests , State Medicine , United Kingdom
11.
Sci Total Environ ; 627: 1345-1352, 2018 Jun 15.
Article in English | MEDLINE | ID: mdl-30857098

ABSTRACT

Mercury (Hg) methylation, a key process in the biogeochemical cycle of Hg, is mainly attributed to sulfate-reducing bacteria and methanogenic Archaea. However, environmental regulation by these groups has not yet been ascertained in tropical environments, especially in respect to the seasonal flood flooding. This work evaluated the variation of net methylmercury production potential in relation to biological characteristics of the periphyton, environmental factors, and flood pulse seasons. Our results indicate that there is a seasonal change between metabolic groups as main Hg methylators, sulfate-reducing bacteria in the dry season and methanogenic Archaea in the flood season. In addition, there was a positive relationship between dissolved organic carbon (DOC), phosphorus, cyanobacteria biovolume, and periphytic Hg methylation potential. These results shed a new light on MeHg production plasticity, mediated by landscape and flood pulses in tropical wetlands, as well as on ecological relationships within the periphyton.


Subject(s)
Environmental Monitoring , Mercury/metabolism , Periphyton/physiology , Water Pollutants, Chemical/metabolism , Wetlands , Biodegradation, Environmental , Seasons
12.
Int J Obes (Lond) ; 41(12): 1831-1834, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28676679

ABSTRACT

Previous research has shown that attachment anxiety is a good predictor of body mass index. This relationship is significantly mediated by disinhibited (over-) eating and is likely to reflect a specific form of affect regulation. This study explored whether obese bariatric surgery candidates (BSC; N=34) and bariatric surgery recipients (BSR; N=15) would show higher levels of attachment insecurity (higher attachment anxiety and/or higher attachment avoidance) than a group of age and gender-matched lean controls (N=54). Mediation analyses showed that compared to lean controls (M=2.96, SE=0.1), both BSC (M=3.5, SE=0.2) and BSR (M=3.4, SE=0.2) groups had a more insecure attachment orientation. These relationships were significantly mediated by disinhibited eating (BSC: lower limit confidence interval (LLCI)=0.06 and upper limit confidence interval (ULCI)=0.62; BSR: LLCI=0.02 and ULCI=0.76). There was no such relationship when the BSC and BSR groups were compared (LLCI=-0.15 & ULCI=0.3). These observations suggest that attachment insecurity may be a risk factor for obesity and bariatric surgery because of associated disinhibited eating. Moreover, these factors may be important to consider when bariatric surgery results in poor outcomes.


Subject(s)
Bulimia/psychology , Obesity, Morbid/psychology , Reactive Attachment Disorder/psychology , Thinness/psychology , Bariatric Surgery , Cross-Sectional Studies , Emotions , Female , Humans , Male , Middle Aged , Psychometrics
13.
Clin Radiol ; 72(9): 799.e1-799.e8, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28457521

ABSTRACT

AIM: To investigate the effect of image processing on cancer detection in mammography. METHODS AND MATERIALS: An observer study was performed using 349 digital mammography images of women with normal breasts, calcification clusters, or soft-tissue lesions including 191 subtle cancers. Images underwent two types of processing: FlavourA (standard) and FlavourB (added enhancement). Six observers located features in the breast they suspected to be cancerous (4,188 observations). Data were analysed using jackknife alternative free-response receiver operating characteristic (JAFROC) analysis. Characteristics of the cancers detected with each image processing type were investigated. RESULTS: For calcifications, the JAFROC figure of merit (FOM) was equal to 0.86 for both types of image processing. For soft-tissue lesions, the JAFROC FOM were better for FlavourA (0.81) than FlavourB (0.78); this difference was significant (p=0.001). Using FlavourA a greater number of cancers of all grades and sizes were detected than with FlavourB. FlavourA improved soft-tissue lesion detection in denser breasts (p=0.04 when volumetric density was over 7.5%) CONCLUSIONS: The detection of malignant soft-tissue lesions (which were primarily invasive) was significantly better with FlavourA than FlavourB image processing. This is despite FlavourB having a higher contrast appearance often preferred by radiologists. It is important that clinical choice of image processing is based on objective measures.


Subject(s)
Breast Neoplasms/diagnostic imaging , Calcinosis/diagnostic imaging , Diagnostic Errors , Mammography/methods , Radiographic Image Interpretation, Computer-Assisted/methods , Aged , Breast Neoplasms/pathology , Calcinosis/pathology , Female , Humans , Middle Aged
14.
Trop Doct ; 47(4): 291-294, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28424019

ABSTRACT

This year marks the 20th anniversary of the Primary Trauma Care Foundation (PTC), which provides a course aimed at providing a systematic approach to trauma and the unwell patient in low- and middle-income countries. The course is based on the original 36-page PTC manual and a key ethos of being appropriate to the target audience, affordable to those who need it, adaptable to the needs of each local area and sustainable to perpetuate itself. The concept is simple: a two-day course for candidates, followed by a one-day instructor course, and finally a first course delivered to local healthcare staff by the first cohort. Now in its 20th year, its reach spans 76 countries, is ingrained in the syllabus of many healthcare systems and continues to reach new territories with a programme shown to produce a measurable improvement in the care delivered.


Subject(s)
Primary Health Care/methods , Wounds and Injuries/therapy , Cohort Studies , Delivery of Health Care/organization & administration , Developing Countries , Global Health , Humans
15.
J Neonatal Perinatal Med ; 10(1): 25-31, 2017.
Article in English | MEDLINE | ID: mdl-28282822

ABSTRACT

OBJECTIVE: Women with diabetes may need elective preterm delivery due to pregnancy or diabetes related complications. The aim of this study was to describe the neonatal outcomes arising from elective preterm delivery in diabetic women. METHOD: Suitable patients were identified by the obstetric team at Hull Royal Infirmary Women and Children's Hospital and data was extracted from their case notes. 45 diabetic women with planned preterm delivery were identified within a set time frame, resulting in 48 babies. RESULTS: Of the 48 babies born, 47 survived. 36 out of 48 were delivered via caesarean section. Gestational ages ranged from 29+3 to 36+6 weeks, and 24 out of 48 (50%) had a birth weight greater than the 90th centile for gestational age.34 out of the 48 babies experienced some form of neonatal complication and were admitted to the neonatal unit. The median duration of stay in the neonatal unit was 7 days. 14 of the surviving neonates suffered from respiratory distress, although only 4 required surfactant therapy to regain respiratory function. However, the incidence of serious neonatal complications in those born after 34 weeks was shown to be low. CONCLUSIONS: Elective preterm delivery after 34 weeks had little effect on overall neonatal outcome. Therefore it could be proposed that elective preterm delivery after 34 weeks gestation may be an acceptable option in diabetic women if there are maternal or obstetric complications.


Subject(s)
Cesarean Section , Diabetes, Gestational/therapy , Labor, Induced , Pregnancy in Diabetics/therapy , Premature Birth , Respiratory Distress Syndrome, Newborn/epidemiology , Adult , Birth Weight , Delivery, Obstetric , Diabetes Mellitus, Type 1 , Diabetes Mellitus, Type 2 , England/epidemiology , Female , Gestational Age , Humans , Infant, Newborn , Infant, Premature , Intensive Care Units, Neonatal , Length of Stay/statistics & numerical data , Pregnancy , Pulmonary Surfactants/therapeutic use , Retrospective Studies , Young Adult
16.
Mol Psychiatry ; 22(2): 178-182, 2017 02.
Article in English | MEDLINE | ID: mdl-27956746

ABSTRACT

Large-scale genomic studies have made major progress in identifying genetic risk variants for schizophrenia. A key finding from these studies is that there is an increased burden of genomic copy number variants (CNVs) in schizophrenia cases compared with controls. The mechanism through which these CNVs confer risk for the symptoms of schizophrenia, however, remains unclear. One possibility is that schizophrenia risk CNVs impact basic associative learning processes, abnormalities of which have long been associated with the disorder. To investigate whether genes in schizophrenia CNVs impact on specific phases of associative learning we combined human genetics with experimental gene expression studies in animals. In a sample of 11 917 schizophrenia cases and 16 416 controls, we investigated whether CNVs from patients with schizophrenia are enriched for genes expressed during the consolidation, retrieval or extinction of associative memories. We show that CNVs from cases are enriched for genes expressed during fear extinction in the hippocampus, but not genes expressed following consolidation or retrieval. These results suggest that CNVs act to impair inhibitory learning in schizophrenia, potentially contributing to the development of core symptoms of the disorder.


Subject(s)
Association Learning/physiology , DNA Copy Number Variations/genetics , Schizophrenia/genetics , Animals , CA1 Region, Hippocampal/metabolism , CA1 Region, Hippocampal/physiology , Case-Control Studies , Conditioning, Classical , Databases, Factual , Fear/physiology , Fear/psychology , Female , Genetic Predisposition to Disease , Genome-Wide Association Study , Humans , Male , Rats
17.
J Public Health (Oxf) ; 39(1): 113-121, 2017 03 01.
Article in English | MEDLINE | ID: mdl-26834190

ABSTRACT

Background: Although mortality from breast cancer is declining, incidence continues to increase and is often detected at routine NHS screening. Most middle aged and older women in England attend for screening every 3 years. Assessing their personal breast cancer risk and providing preventative lifestyle advice could help to further reduce breast cancer incidence. Methods: A cross-sectional, self-complete postal survey measured attendees' interest in having a personal risk assessment, expected impact on screening attendance, knowledge of associations between lifestyle and breast cancer and preferred ways of accessing preventative lifestyle advice. Results: A total of 1803/4948 (36.4%) completed questionnaires were returned. Most participants (93.7%) expressed interest in a personal risk assessment and 95% (1713/1803) believed it would make no difference or encourage re-attendance. Two-thirds (1208/1803) associated lifestyle with breast cancer, but many were unaware of specific risks such as weight gain, obesity, alcohol consumption and physical inactivity. NHS sourced advice was expected to be more credible than other sources, and booklets, brief counselling or an interactive website were most preferred for accessing this. Conclusions: Attendees appear to welcome an intervention that would facilitate more proactive clinical and lifestyle prevention and address critical research gaps in breast cancer prevention and early detection.


Subject(s)
Breast Neoplasms/diagnosis , Counseling , Early Detection of Cancer , Aged , Cross-Sectional Studies , Female , Health Knowledge, Attitudes, Practice , Health Promotion , Humans , Life Style , London , Mammography , Middle Aged , State Medicine , Surveys and Questionnaires
18.
Neuropsychologia ; 93(Pt A): 53-60, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27686948

ABSTRACT

Empirical evidence suggests that levodopa medication used to treat the motor symptoms of Parkinson's disease (PD) may either improve, impair or not affect specific cognitive processes. This evidence led to the 'dopamine overdose' hypothesis that levodopa medication impairs performance on cognitive tasks if they recruit fronto-striatal circuits which are not yet dopamine-depleted in early PD and as a result the medication leads to an excess of dopamine. This hypothesis has been supported for various learning tasks including conditional associative learning, reversal learning, classification learning and intentional deterministic sequence learning, on all of which PD patients demonstrated significantly worse performance when tested on relative to off dopamine medication. Incidental sequence learning is impaired in PD, but how such learning is affected by dopaminergic therapy remains undetermined. The aim of the current study was to investigate the effect of dopaminergic medication on incidental sequence learning in PD. We used a probabilistic serial reaction time task (SRTT), a sequence learning paradigm considered to make the sequence less apparent and more likely to be learned incidentally rather than intentionally. We compared learning by the same group of PD patients (n=15) on two separate occasions following oral administration of levodopa medication (on state) and after overnight withdrawal of medication (off state). Our results demonstrate for the first time that levodopa medication enhances incidental learning of a probabilistic sequence on the serial reaction time task in PD. However, neither group significantly differed from performance of a control group without a neurological disease, which indicates the importance of within group comparisons for identifying deficits. Levodopa medication enhanced incidental learning by patients with PD on a probabilistic sequence learning paradigm even though the patients were not aware of the existence of the sequence or their acquired knowledge. The results suggest a role in acquiring incidental motor sequence learning for dorsal striatal areas strongly affected by dopamine depletion in early PD.


Subject(s)
Antiparkinson Agents/therapeutic use , Dopamine Agents/therapeutic use , Levodopa/therapeutic use , Motor Skills/drug effects , Parkinson Disease/drug therapy , Probability Learning , Aged , Analysis of Variance , Awareness/drug effects , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Nootropic Agents/therapeutic use , Parkinson Disease/physiopathology , Parkinson Disease/psychology , Reaction Time , Recognition, Psychology/drug effects , Severity of Illness Index
19.
Genes Brain Behav ; 15(8): 693-701, 2016 11.
Article in English | MEDLINE | ID: mdl-27509352

ABSTRACT

Genomic imprinting is the process whereby germline epigenetic events lead to parent-of-origin specific monallelic expression of a number of key mammalian genes. The imprinted gene Nesp is expressed from the maternal allele only and encodes for Nesp55 protein. In the brain, Nesp55 is found predominately in discrete areas of the hypothalamus and midbrain. Previously, we have shown that loss of Nesp55 gives rise to alterations in novelty-related behaviour. Here, we extend these findings and demonstrate, using the Nespm/+ mouse model, that loss of Nesp55 leads to impulsive choices as measured by a delayed-reinforcement task, whereby Nespm/+ mice were less willing to wait for a delayed, larger reward, preferring instead to choose an immediate, smaller reward. These effects were highly specific as performance in another component of impulsive behaviour, the ability to stop a response once started as assayed in the stop-signal reaction time task, was equivalent to controls. We also showed changes in the serotonin system, a key neurotransmitter pathway mediating impulsive behaviour. First, we demonstrated that Nesp55 is co-localized with serotonin and then went on to show that in midbrain regions there were reductions in mRNA expression of the serotonin-specific genes Tph2 and Slc6a4, but not the dopamine-specific gene Th in Nespm/+ mice; suggesting an altered serotonergic system could contribute, in part, to the changes in impulsive behaviour. These data provide a novel mode of action for genomic imprinting in the brain and may have implications for pathological conditions characterized by maladaptive response control.


Subject(s)
Chromogranins/genetics , GTP-Binding Protein alpha Subunits, Gs/genetics , Genomic Imprinting , Impulsive Behavior/physiology , Alleles , Animals , Choice Behavior/physiology , Chromogranins/metabolism , DNA Methylation , Dopamine/genetics , Dopamine/metabolism , Epigenesis, Genetic , GTP-Binding Protein alpha Subunits, Gs/metabolism , Male , Maternal Inheritance , Mice , Mice, Inbred C57BL , Reinforcement, Psychology , Serotonin/genetics , Serotonin/metabolism
20.
Environ Res ; 150: 438-445, 2016 10.
Article in English | MEDLINE | ID: mdl-27376931

ABSTRACT

The periphyton associated with freshwater macrophyte roots is the main site of Hg methylation in different wetland environments in the world. The aim of this study was to test the use of connectivity metrics of water bodies, in the context of patches, in a tropical waterscape wetland (Guapore River, Amazonia, Brazil) as a predictor of potential net methylmercury (MeHg) production by periphyton communities. We sampled 15 lakes with different patterns of lateral connectivity with the main river channel, performing net mercury methylation potential tests in incubations with local water and Eichhornia crassipes root-periphyton samples, using (203)HgCl2 as a tracer. Physico-chemical variables, landscape data (morphological characteristics, land use, and lateral connection type of water bodies) using GIS resources and field data were analyzed with Generalized Additive Models (GAM). The net Me(203)Hg production (as % of total added (203)Hg) was expressive (6.2-25.6%) showing that periphyton is an important matrix in MeHg production. The model that best explained the variation in the net Me(203)Hg production (76%) was built by the variables: connection type, total phosphorus and dissolved organic carbon (DOC) in water (AICc=48.324, p=0.001). Connection type factor was the best factor to model fit (r(2)=0.32; p=0.008) and temporarily connected lakes had higher rates of net mercury methylation. Both DOC and total phosphorus showed positive significant covariation with the net methylation rates (r(2)=0.26; p=0.008 and r(2)=0.21; p=0.012 respectively). Our study suggests a strong relationship between rates of net MeHg production in this tropical area and the type of water body and its hydrological connectivity within the waterscape.


Subject(s)
Methylmercury Compounds/metabolism , Water Pollutants, Chemical/metabolism , Brazil , Eichhornia/metabolism , Environmental Monitoring , Hydrology , Lakes , Linear Models , Methylation , Methylmercury Compounds/analysis , Tropical Climate , Water Pollutants, Chemical/analysis , Wetlands
SELECTION OF CITATIONS
SEARCH DETAIL
...